Melody Key

The Melody Key is a magical item often used by Kuromi, there are multiple variations of the item in existence, with many said to be knockoffs.

Physical Attributes
The Melody Key usually appears as a large yellow key with a diamond shaped black gem above its hilt. The key has three ridges at the top with the lowest notch being shaped like a diamond.

Abilities
The Melody Key's main function as first introduced is to open the doors to a human's dreams with the power of nightmare magic. This magic is often unstable which can lead to things spiralling out of control, though if a human is satisfied with how their dream was fulfilled, a Black Note will be produced.

Conversely, the function of the Melody Key in its prototype state was not to open dream doors, instead being a transformation device, having the ability to change the form of the holder's partner. This functionality is likewise retained by the Dark Melody Key.

The Melody Key needs to regularly be charged by a magical instrument in order to function. However, the Dark Melody Key and the Prototype Melody Key are without this flaw.

Melody Key (Onegai My Melody)
The first Melody Key seen is discovered by Kuromi and Baku shortly before the events of Onegai My Melody in the Mari Land castle dungeon, in a room next to their cell. With it, they find the Melody Bow and a usage manual, only to lose the latter.

Melody Key (~Kuru Kuru Shuffle~)
In Onegai My Melody Kuru Kuru Shuffle, Kuromi and Baku find yet another Melody Key in the same room as before, this time in the hands of a suit of armour.

Dark Melody Key
Featuring in Onegai My Melody Sukkiri♪, the Dark Melody Key is given to Kuromi by a mysterious stranger.

Prototype Melody Key
Featuring in Onegai My Melody Kirara★, the prototype Melody Key was found in the Mari Land castle dungeon by Kuromi and Baku.

Other Appearances
In the trick art for the Hello Kitty Japan DiverCity Tokyo Plaza Store Kuromi Takeover, the gem inside the Melody Key is depicted as being purple, despite it retaining its usual black colouration in the promotional video.

Merchandise
In 2006, a Melody Key toy was released by toy manufacturer Pinocchio.